Structural Modelling of Wire Ropes

[SewardWyon]

We have just acquired a copy of SCIA Engineer 2008.1 structural analysis and FEA software, and I am the primary user of this software. I am designing a flare boom for mounting on deep sea drilling ships. It is a lattice structure, triangular in section, is hinged at the root where it connects to the ship and supported by guy wires anchored 15m above the boom root and attaching to 2 points approxiamatly 1/3 and 2/3 along its length. The problem I have is modelling the wire ropes realistically, so that the catenary and spring effects of the rope are taken into account. Both these factors could contribute to the boom resonating at its natural frequency.
Thanks in advance

 

[GregLocock]

Well, with no answers I'll take a stab.

You can either model them as tension members, and then use a linear analysis, or else you'll have to do a non linear analysis in which case your 'resonant frequencies' will change with excitation amplitude. That is a pain.

If you can assume that the wires stay in tension all the time, and that their self resonances are unimportant, then the linear approach should work.




Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.